1. Field of the Invention
The present invention relates to a motor driving apparatus and, more particularly, it relates to a motor driving apparatus that feeds electric power, stored during regeneration, to an electric power source.
2. Description of the Related Art
In a motor driving apparatus, a large driving current flows during normal power operation and a regenerative current flows during deceleration. Therefore, the motor driving apparatus has to be designed in consideration of the peak current during normal power operation and, as a result, it is forced to be large in size and expensive. Further, the regenerative current generated during deceleration is fed to a resistor so that it is transformed into thermal energy and consumed and, therefore, the energy is wastefully lost.
As a measure to solve these problems, a motor driving apparatus disclosed in Japanese Unexamined Patent Publication No. 2000-141440 includes a power source rectifier circuit for converting AC electric power into DC electric power, an inverter circuit for converting DC electric power into AC electric power to drive an AC motor, and a DC link for connecting the power source rectifier circuit with the inverter circuit, wherein a capacitor is connected with the DC link.
Here, the electric power stored in the capacitor is supplied to the inverter circuit during acceleration of the motor, while the regenerative current is stored in this capacitor during deceleration of the motor, so that the driving current can be leveled and the regenerative current is not be consumed wastefully.